Atsushi Takayasu
Associate Professor in the University of Tokyo, Graduate School of Information Science and Technology, Tokyo, Japan
I am a member of Mathematical Informatics 1st Laboratory in the Department of Mathematical Informatics.
My research interest is cryptography, especially lattices, lattice reductions, quantum algorithms, attribute-based encryption, and cryptanalysis.
See dblp, google scholar citations, ORCID.
e-mail: takayasu-a[at]g.ecc.u-tokyo.ac.jp
Bachelor of Engineering from Mathematical Engineering Course, Department of Mathematical Engineering and Information Physics, Faculty of Engineering, The University of Tokyo, March 2012.
Master of Science from Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo, March 2014. (Supervisor, Noboru Kunihiro)
JSPS Research Fellowship for Young Scientists (DC1), April 2014 - March 2017.
Ph.D of Science from Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo, March 2017. (Supervisor, Noboru Kunihiro)
Collaborative researcher in National Institute of Advanced Industrial Science and Technology (AIST), April 2015 - March 2020.
Research associate in the University of Tokyo, Graduate School of Information Science and Technology, Department of Mathematical Informatics, April 2017 - March 2020.
Invited advisor in National Institute of Information and Communications Technology (NICT), September 2019 - March 2020.
Senior researcher in National Institute of Information and Communications Technology (NICT), April 2020 - September 2021.
Lecturer in the University of Tokyo, Graduate School of Information Science and Technology, Department of Mathematical Informatics, October 2021 - November 2023.
Associate Professor in the University of Tokyo, Graduate School of Information Science and Technology, Department of Mathematical Informatics, December 2023 -.
Refereed International Journal
Ren Taguchi and Atsushi Takayasu. Concrete Quantum Cryptanalysis of Binary Elliptic Curves via Addition Chain. Quantum Information Processing, Volume 23, 122, 2024.
Kyoichi Asano, Keita Emura, and Atsushi Takayasu. More Efficient Adaptively Secure Lattice-based IBE with Equality Test in the Standard Model. IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences (Special Section on Cryptography and Information Security), E107-A, No. 3, pp. 248-259, 2024.
Kohei Nakagawa, Hiroshi Onuki, Atsushi Takayasu, and Tsuyoshi Takagi. L_1-Norm Ball for CSIDH: Optimal Strategy for Choosing the Secret Key Space. Discrete Applied Mathematics. Vol. 328, pp. 70 - 88, 2023. [ePrint]
Keita Emura and Atsushi Takayasu. A Generic Construction of CCA-secure Identity-based Encryption with Equality Test against Insider Attacks. IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences (Special Section on Cryptography and Information Security), E106-A, No. 3, pp. 193-202, 2023.
Keita Emura, Atsushi Takayasu, and Yohei Watanabe. Efficient Identity-based Encryption with Hierarchical Key-Insulation from HIBE. Designs, Codes and Cryptography. Vol. 89, issue 10, pp. 2397 - 2431, 2021. [ePrint]
Hiroki Okada, Atsushi Takayasu, Kazuhide Fukushima, Shinsaku Kiyomoto, and Tsuyoshi Takagi. A Compact Digital Signature Scheme Based on the Module-LWR Problem. IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences (Special Section on Discrete Mathematics and Its Applications), E104-A, No. 9, pp. 1219 - 1234, 2021.
Atsushi Takayasu. Adaptively Secure Lattice-based Revocable IBE in the QROM: Compact Parameters, Tight Security, and Anonymity. Designs, Codes and Cryptography. Vol. 89, issue 8, pp. 1965 - 1992, 2021. [ePrint]
Atsushi Takayasu. Tag-based ABE in Prime-order Groups via Pair Encoding. Designs, Codes and Cryptography. Vol. 89, issue 8, pp. 1927 - 1963, 2021.
Keita Emura, Atsushi Takayasu, and Yohei Watanabe. Adaptively Secure Revocable Hierarchical IBE from k-linear Assumption. Designs, Codes and Cryptography. Vol. 89, issue 7, pp. 1535 - 1574, 2021. [ePrint]
Atsushi Takayasu and Yohei Watanabe. Revocable Identity-based Encryption with Bounded Decryption Key Exposure Resistance: Lattice-based Construction and More. Theoretical Computer Science, Vol. 849, pp. 64 - 98, 2021.
Kaichi Suzuki, Atsushi Takayasu, and Noboru Kunihiro. Extended Partial Key Exposure Attacks on RSA: Improvement up to Full Size Decryption Exponents. Theoretical Computer Science, Vol. 841, pp. 62 - 83, 2020.
Noboru Kunihiro and Atsushi Takayasu. Worst Case Short Lattice Vector Enumeration on Block Reduced Bases of Arbitrary Blocksizes. Discrete Applied Mathematics. Vol. 277, pp. 198 - 220, 2020.
Shuichi Katsumata, Takahiro Matsuda, and Atsushi Takayasu. Lattice-based Revocable (Hierarchical) IBE with Decryption Key Exposure Resistance. Theoretical Computer Science, Vol. 809, pp. 103-136, 2020.
Hiroki Okada, Atsushi Takayasu, Kazuhide Fukushima, Shinsaku Kiyomoto, and Tsuyoshi Takagi. On the complexity of the LWR-Solving BKW Algorithm. IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences (Special Section on Cryptography and Information Security), E103-A, No. 1, pp. 173 - 182, 2020.
Liqiang Peng and Atsushi Takayasu. Generalized Cryptanalysis of Small CRT-Exponent RSA. Theoretical Computer Science, Vol. 795, pp. 432-458, 2019.
Kotaro Matsuda, Atsushi Takayasu, and Tsuyoshi Takagi. Explicit Relation between Low-dimensional LLL-reduced Bases and Shortest Vectors. IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences (Special Section on Discrete Mathematics and Its Applications), E102-A, No. 9, pp. 1091-1100, 2019.
Atsushi Takayasu, Yao Lu, and Liqiang Peng. Small CRT-exponent RSA Revisited. Journal of Cryptology. Vol. 32, Issue 4, pp. 1337-1382, 2019.
Atsushi Takayasu and Noboru Kunihiro. Partial Key Exposure Attacks on RSA: Achieving the Boneh-Durfee Bound. Theoretical Computer Science, Vol. 761, pp. 51-77, 2019.
Atsushi Takayasu and Noboru Kunihiro. General Bounds for Small Inverse Problems and Its Applications to Multi-Prime RSA. IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences (Special Section on Cryptography and Information Security), Vol. E100-A, No. 1, pp. 50-61, 2017.
Atsushi Takayasu and Noboru Kunihiro. Better Lattice Constructions for Solving Multivariate Linear Equations Modulo Unknown Divisors. IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences (Special Section on Discrete Mathematics and Its Applications), Vol. E97-A, No. 6, pp. 1259-1272, 2014.
Refereed International Conference Proceeding
Ren Taguchi and Atsushi Takayasu. On the Untapped Potential of the Quantum FLT-based Inversion. Proc. ACNS 2024, LNCS 14584, pp. 79-100, Springer, 2024. (presented by the first author) [ePrint]
Yen-Ting Kuo and Atsushi Takayasu. A Lattice Attack on CRYSTALS-Kyber with Correlation Power Analysis. Proc. ICISC 2023, LNCS 14561, pp. 202-220, Springer, 2024. (presented by the first author) [ePrint]
Naoto Kimura, Atsushi Takayasu, and Tsuyoshi Takagi. Memory-Efficient Quantum Information Set Decoding Algorithm. Proc. ACISP 2023, LNCS 13915, pp. 452-468, Springer, 2023.
Ren Taguchi and Atsushi Takayasu. Concrete Quantum Cryptanalysis of Binary Elliptic Curves via Addition Chain. Proc. CT-RSA 2023, LNCS 13871, pp. 57-83, Springer, 2023. (presented by the first author) [ePrint]
Kyoichi Asano, Keita Emura, and Atsushi Takayasu. More Efficient Adaptively Secure Lattice-based IBE with Equality Test in the Standard Model. Proc. ISC 2022, LNCS 13640, pp. 75-83, 2022. (presented by the first author) [ePrint]
Kyoichi Asano, Keita Emura, Atsushi Takayasu, and Yohei Watanabe. A Generic Construction of CCA-Secure Attribute-Based Encryption with Equality Test. Proc. ProvSec 2022, LNCS 13600, pp. 3-19, 2022. (presented by the first author, Best Paper Award) [ePrint]
Shingo Sato, Keita Emura, and Atsushi Takayasu. Keyed-Fully Homomorphic Encryption without Indistinguishability Obfuscation. Proc. ACNS 2022, LNCS 13269, pp. 3-23, Springer, 2022. (presented by the first author) [ePrint]
Hiroki Okada, Atsushi Takayasu, Kazuhide Fukushima, Shinsaku Kiyomoto, and Tsuyoshi Takagi. A Compact Digital Signature Scheme Based on the Module-LWR Problem. Proc. ICICS 2020, LNCS 12282, pp. 73-90, Springer, 2020. (presented by the first author) [ePrint]
Shuichi Katsumata, Takahiro Matsuda, and Atsushi Takayasu. Lattice-based Revocable (Hierarchical) IBE with Decryption Key Exposure Resistance. Proc. PKC 2019, LNCS 11443, pp. 441-471, Springer, 2019. [ePrint], [slide]
Taiga Mizuide, Atsushi Takayasu, and Tsuyoshi Takagi. Tight Reductions for Diffie-Hellman Variants in the Algebraic Group Model. Proc. CT-RSA 2019, LNCS 11405, pp. 169-188, Springer, 2019. [ePrint], [slide]
Hiroki Okada, Atsushi Takayasu, Kazuhide Fukushima, Shinsaku Kiyomoto, and Tsuyoshi Takagi. On the complexity of the LWR-Solving BKW Algorithm. Proc. ICISC 2018, LNCS 11396, pp. 196-214, Springer, 2018. (presented by the first author)
Weiyao Wang, Yuntao Wang, Atsushi Takayasu, and Tsuyoshi Takagi. Estimated Cost for Solving Generalized Learning with Errors Problem via Embedding Techniques. Proc. IWSEC 2018, LNCS 11049, pp. 87-103, Springer, 2018. (presented by the first author, Best Student Paper Award)
Atsushi Takayasu and Yohei Watanabe. Lattice-based Revocable Identity-based Encryption with Bounded Decryption Key Exposure Resistance. Proc. ACISP 2017, LNCS 10342, pp. 184-204, Springer, 2017. [ePrint]
Atsushi Takayasu, Yao Lu, and Liqiang Peng. Small CRT-exponent RSA Revisited. Proc. Eurocrypt 2017, LNCS 10211, pp. 130-159, Springer, 2017. [ePrint], [slide], [youtube]
Atsushi Takayasu and Noboru Kunihiro. A Tool Kit for Partial Key Exposure Attacks on RSA. Proc. CT-RSA 2017, LNCS 10159, pp. 58-73, Springer, 2017. [ePrint], [slide]
Atsushi Takayasu and Noboru Kunihiro. Small Secret Exponent Attacks on RSA with Unbalanced Prime Factors. Proc. ISITA 2016, pp. 236-240, IEEE, 2016.
Atsushi Takayasu and Noboru Kunihiro. Partial Key Exposure Attacks on CRT-RSA: General Improvement for the Exposed Least Significant Bits. Proc. ISC 2016, LNCS 9866, pp. 35-47, Springer, 2016.
Atsushi Takayasu and Noboru Kunihiro. Partial Key Exposure Attacks on RSA with Multiple Exponent Pairs. Proc. ACISP 2016, LNCS 9723, pp. 243-257, Springer, 2016. (Best Student Paper Award)
Atsushi Takayasu and Noboru Kunihiro. How to Generalize RSA Cryptanalyses. Proc. PKC 2016, LNCS 9615, pp. 67-97, Springer 2016. [ePrint], [slide]
Katsuyuki Takashima and Atsushi Takayasu. Tighter Security for Efficient Lattice Cryptography via the Renyi Divergence of Optimized Orders. Proc. ProvSec 2015, LNCS 9451, pp. 412-431, Springer, 2015. [ePrint], [slide]
Atsushi Takayasu and Noboru Kunihiro. Partial Key Exposure Attacks on CRT-RSA: Better Cryptanalysis to Full Size Encryption Exponents. Proc. ACNS 2015, LNCS 9092, pp. 518-537, Springer, 2015.
Atsushi Takayasu and Noboru Kunihiro. General Bounds for Small Inverse Problems and Its Applications to Multi-Prime RSA. Proc. ICISC 2014, LNCS 8949, pp. 3-17, Springer, 2014. [ePrint]
Atsushi Takayasu and Noboru Kunihiro. Partial Key Exposure Attacks on RSA: Achieving the Boneh-Durfee Bound. Proc. SAC 2014, LNCS 8781, pp. 345-362, Springer, 2014. [ePrint]
Atsushi Takayasu and Noboru Kunihiro. Cryptanalysis of RSA with Multiple Small Secret Exponents. Proc. ACISP 2014, LNCS 8544, pp. 176-191, Springer 2014.
Atsushi Takayasu and Noboru Kunihiro. Better Lattice Constructions for Solving Multivariate Linear Equations Modulo Unknown Divisors. Proc. ACISP 2013, LNCS 7959, pp. 118-135, Springer, 2013.
Other International Conference Talks
Kaichi Suzuki, Atsushi Takayasu, and Noboru Kunihiro. Extended Partial Key Exposure Attack on RSA. Poster session in IWSEC 2018, 2018. (presented by the first author)
Kotaro Matsuda, Atsushi Takayasu, and Tsuyoshi Takagi. Explicit Relation between Low-dimensional LLL-reduced Bases and the Shortest Vectors. AAAC2018, 2018. （presented by the first author）
Atsushi Takayasu. Parameter Selections for Approximate GCD Problems. SCIS/CSS Invited Session in IWSEC 2016, 2016.
Atsushi Takayasu and Noboru Kunihiro. Faster LLL Reduction to Break the Security of Fully Homomorphic Encryption and Multilinear Map over the Integers. Poster session in IWSEC 2015, 2015.
Atsushi Takayasu. Improved Algorithms for Partial Key Exposure Attacks on RSA. SCIS/CSS Invited Session in IWSEC 2014, 2014.
Atsushi Takayasu and Noboru Kunihiro. Partial Key Exposure Attacks on RSA When Most Significant Bits of d Known. Poster session in ACM ASIACCS 2014, 2014.
Atsushi Takayasu and Noboru Kunihiro. Partial Key Exposure Attacks on RSA: Achieve Boneh-Durfee's Bound. Poster session in IWSEC 2013, 2013.
Awards
Best Paper Award, ProvSec 2022, November 2022.
Best Student Paper Award, IWSEC 2018, September 2018.
Best Student Paper Award, ACISP 2016, July 2016.
Other Talks
Solving RSA and Factoring Problems Using LLL Reduction. Workshop on analysis of mathematical cryptography via algebraic methods, February 2018．
Small CRT-exponent RSA Revisited. NTT-JFLI-U.Tokyo Workshop on Cryptography, January 2018.
Small CRT-exponent RSA Revisited. Tokyo Crypto Day, June 2017.
Professional Activities
Program Committee：ProvSec2024, PQCrypto2024, ACISP 2024, Indocrypt2023, FCS 2023, PQCrypto2023, ProvSec2023, APKC2023, Indocrypto2022, ISC2022, ACISP2022, APKC2022, PKC2022, ICISC2021, Provsec2021, IWSEC2021, APKC2021, ICISC2020, ISC2020, Provsec2020, IWSEC2020, APKC2020, PKC2020, ProvSec2019, IWSEC2019, ACISP2019, APKC2019, Indocrypt2018, ProvSec2018, ACISP2018, APKC2018, ICISC2017
Editorial Committee Member: Journal of Information Processing Special issue of "Computer Security Technologies for Secure Cyberspace" (published September 2023)
Guest Associate Editor: IEICE Transactions on Electronics, Communications and Computer Sciences Special Section on Discrete Mathematics and Its Applications (published September 2023)